When you have a trap placed as in the top image, even though it looks like it's accessible, since it is rotated the wrong way you can't load the trap. You'll see once that tile was removed the trap rotates on its own and it begins working again. I tried using the rotate tool to rotate the trap itself, but it didn't do anything.

I reconstructed the way Mello made build this trap and I can confirm that thanks to rotation tool I could set it on proper direction. However I didn't know which direction is my trap facing - could you add to mouse trap and barbecue directional arrows like you add for example for Well?

I don't think the Mouse Trap is omnidirectional because I had an instance in a previous version where Imps weren't reaching the trap because it was facing the wrong way. Having it be omnidirectional makes sense though.